Method for smelting alloy steel

Abstract

This invention discloses a method for smelting alloy steel, comprising: selecting scrap steel that meets the addition conditions as additive, wherein the types of elements included in the scrap steel are within the range of types of elements included in the molten steel; determining the maximum amount of additive to be added based on the total amount of molten steel; adding a set amount of additive to the molten steel, wherein the set amount is less than or equal to the maximum amount to be added; determining the temperature drop of the molten steel based on the set amount and the total amount of molten steel, and performing temperature compensation on the molten steel; detecting the content of each element in the molten steel, and performing compensation treatment on the molten steel based on the detection results. This method avoids the waste of alloy resources, effectively recovers and utilizes high-value alloy elements in scrap steel, and significantly reduces alloy costs. Furthermore, it reduces production capacity loss, as scrap steel is directly melted into molten steel, increasing steel production and improving single-furnace capacity and continuous casting efficiency. It avoids the additional costs and environmental burden caused by scrap steel stockpiling, transportation, and treatment as ordinary scrap steel.

Description

Technical Field

[0001] This application relates to the field of iron and steel smelting technology, and more particularly to a method for smelting alloy steel. Background Technology

[0002] During the smelting of alloy steel, some scrap billets are generated. These scrap billets contain a large number of high-value alloying elements. In related technologies, alloy steel scrap billets are treated as ordinary scrap steel and recycled. However, due to the complexity of the composition, it is difficult to control it precisely. Therefore, they cannot be effectively consumed in the smelting of conventional steel grades, resulting in a waste of alloy resources. Summary of the Invention

[0003] This application aims to address at least one of the technical problems existing in the prior art or related technologies.

[0004] In view of this, a method for smelting alloy steel is proposed according to the technical solution of this application, comprising: selecting scrap steel that meets the addition conditions as additive, wherein the addition conditions are that the types of elements included in the scrap steel are within the range of the types of elements included in the molten steel; determining the maximum addition amount of additive based on the total amount of molten steel; adding a set amount of additive to the molten steel, wherein the set amount is less than or equal to the maximum addition amount; determining the temperature drop of the molten steel based on the set amount and the total amount of molten steel, and performing temperature compensation on the molten steel; detecting the content of each element in the molten steel, and performing compensation treatment on the molten steel based on the detection results.

[0005] In some of the technical solutions provided in this application, the added condition also includes that the length of the scrap steel is less than or equal to a preset length.

[0006] In some technical solutions provided in this application, adding a set amount of additive to molten steel includes: dividing the set amount of additive into multiple sub-additives, and adding the multiple sub-additives to the molten steel in sequence.

[0007] In some of the technical solutions provided in this application, the time interval between two adjacent additions of sub-materials is greater than or equal to the first time interval.

[0008] In some of the technical solutions provided in this application, the weight of any one component added is less than or equal to the preset weight.

[0009] In some of the technical solutions provided in this application, temperature compensation for molten steel includes: heating the molten steel with an electric arc to bring the temperature of the molten steel to a first target temperature.

[0010] In some technical solutions provided in this application, before adding a set amount of additive to the molten steel, the following steps are also included: confirming whether the temperature of the molten steel is lower than the second target temperature; if the temperature of the molten steel is lower than the second target temperature, heating the molten steel to the second target temperature; if the temperature of the molten steel is higher than or equal to the second target temperature, adding the first total amount of additive to the molten steel.

[0011] In some technical solutions provided in this application, before adding a set amount of additive to the molten steel, the following steps are also included: confirming whether the liquid level of the molten steel is lower than the liquid level threshold; if the liquid level of the molten steel is lower than the liquid level threshold, then adding a set amount of additive to the molten steel; if the liquid level of the molten steel is equal to or higher than the liquid level threshold, then stopping the addition of the set amount of additive to the molten steel.

[0012] In some of the technical solutions provided in this application, after adding a set amount of feed material to the molten steel, the method further includes: stirring the molten steel with argon and keeping the stirred molten steel stationary for a second time.

[0013] In some of the technical solutions provided in this application, the molten steel is compensated based on the test results, including: adding a desulfurizing agent to the molten steel when the sulfur content in the molten steel is greater than a preset threshold.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: This application enables the reuse of scrap steel containing alloying elements by adding qualified scrap steel to molten steel. Compared to existing alloy steel smelting methods, this method avoids the waste of alloy resources, effectively recovers and utilizes high-value alloying elements from the scrap steel, and significantly reduces alloy costs. Furthermore, it reduces production capacity loss, as the scrap steel is directly melted into the molten steel, increasing steel output and improving single-furnace capacity and continuous casting efficiency. It also avoids the additional costs and environmental burden associated with scrap steel storage, transportation, and treatment as ordinary scrap steel. Attached Figure Description

[0015] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This illustration shows one of the process flow diagrams of an alloy steel smelting method provided in an embodiment of this application; Figure 2 This is a second schematic flowchart of an alloy steel smelting method provided in an embodiment of this application; Figure 3 This is shown as a third schematic flowchart of an alloy steel smelting method provided in an embodiment of this application; Figure 4 The fourth schematic diagram of an alloy steel smelting method provided in this application embodiment is shown. Figure 5 The fifth schematic diagram shows a process flow diagram of an alloy steel smelting method provided in this application embodiment; Figure 6 This is shown as a sixth schematic flowchart of an alloy steel smelting method provided in an embodiment of this application; Figure 7 The seventh illustration shows a process flow diagram of an alloy steel smelting method provided in this application embodiment. Detailed Implementation

[0016] To better understand the above technical solutions, the technical solutions of the embodiments of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of this application and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of this application, rather than limitations on the technical solutions of this application. In the absence of conflict, the embodiments of this application and the technical features in the embodiments can be combined with each other.

[0017] The following reference Figures 1 to 7 A method for smelting alloy steel according to some embodiments of the present invention is described.

[0018] This application provides a method for smelting alloy steel, such as... Figure 1 As shown, the method includes: 102: Select scrap steel that meets the addition conditions as the additive material. The addition conditions are that the types of elements included in the scrap steel are within the range of the types of elements included in the molten steel. 104: Determine the maximum amount of additives to be added based on the total amount of molten steel; 106: Add a set amount of additive to the molten steel, the set amount being less than or equal to the maximum amount to be added; 108: Determine the temperature drop of the molten steel based on the set amount and the total amount of molten steel, and perform temperature compensation on the molten steel; 110: The content of each element in the molten steel is tested, and the molten steel is compensated according to the test results.

[0019] The alloy steel smelting method proposed in this application enables the reuse of scrap steel containing alloying elements by melting the scrap steel into molten steel. This increases steel production while reducing the costs associated with scrap steel storage, transportation, and processing. First, the scrap steel is screened to select those meeting the addition criteria. The addition criteria require that the types of elements in the scrap steel be within the range of elements present in the molten steel. In one possible embodiment, if the molten steel contains only chromium, then the scrap steel meeting the addition criteria can only contain chromium-related elements. In another possible embodiment, if the molten steel contains both chromium and molybdenum, then the scrap steel meeting the addition criteria can only contain either chromium-related elements or chromium-molybdenum-related elements. In yet another possible embodiment, if the molten steel contains chromium, molybdenum, and nickel, then the scrap steel meeting the addition criteria can only contain either chromium-related elements, chromium-molybdenum-related elements, or chromium-molybdenum-nickel-related elements. In another possible embodiment, the alloying elements in the molten steel include chromium, molybdenum, and vanadium. Therefore, the scrap steel meeting the addition criteria can only contain chromium-based, chromium-molybdenum, or chromium-molybdenum-vanadium-based elements. This avoids the introduction of other alloying elements into the molten steel.

[0020] Furthermore, after identifying the scrap steel that meets the addition criteria as the feedstock, it is also necessary to determine the total amount of feedstock that can be added to the molten steel. Specifically, the maximum amount of feedstock to be added is first determined based on the total amount of molten steel, and then a set amount of feedstock is added to the molten steel, which is less than or equal to the maximum amount. This ensures that too much scrap steel is not added, avoiding excessive temperature drop in the molten steel. In one possible embodiment, the maximum amount of feedstock to be added is less than or equal to 5% of the total amount of molten steel.

[0021] Furthermore, after adding a predetermined amount of additive to the molten steel, the temperature of the molten steel will drop. The temperature drop is calculated based on the predetermined amount and the total amount of molten steel, and temperature compensation is performed to ensure that the temperature of the molten steel meets the casting requirements. In another possible embodiment, the temperature of the molten steel can also be detected after adding scrap steel to obtain the temperature drop.

[0022] Furthermore, after the scrap steel in the molten steel has completely melted, the content of each element in the molten steel is tested, and the molten steel is compensated according to the test results. In one possible embodiment, a set amount of scrap steel is added to the molten steel, and after stirring thoroughly for more than 10 minutes, the molten steel is sampled, and key elements such as carbon, silicon, manganese, and sulfur in the molten steel are analyzed. If the sulfur content exceeds the standard, desulfurizing agent is immediately added to the molten steel and stirring is intensified.

[0023] By adding qualified scrap steel to molten steel, scrap steel containing alloying elements can be reused. Compared to existing alloy steel smelting methods, this method avoids the waste of alloy resources, effectively recovers and utilizes high-value alloying elements from scrap steel, and significantly reduces alloy costs. Furthermore, it reduces production capacity loss, as the scrap steel is directly melted into the molten steel, increasing steel output and improving single-furnace capacity and continuous casting efficiency. It also avoids the additional costs and environmental burden associated with scrap steel storage, transportation, and treatment as ordinary scrap steel.

[0024] The alloy steel smelting method proposed in this application has significant economic benefits, with a cost reduction of up to 488 yuan per furnace and up to 988,000 yuan per casting. It has been successfully applied in steel plants to multiple grades of high alloy special steel, such as H13, H11, and 18CrNi8.

[0025] In some embodiments, the inclusion condition may optionally include the length of the scrap steel being less than or equal to a preset length.

[0026] In this embodiment, the addition conditions are further defined. These conditions also include limitations on the size of the scrap steel. Specifically, the scrap steel can be the head and tail billets produced by continuous casting. If the size of the billets is too large, it can easily cause jamming problems. Therefore, the size of the scrap steel is limited; the length of the scrap steel should be less than or equal to a preset length, which can be 2 meters. By limiting the size of the scrap steel, jamming problems can be avoided when adding molten steel.

[0027] In addition, the cleanliness of scrap steel can be restricted; for example, the scrap steel selected as feed material should be kept away from pollution sources.

[0028] Furthermore, before hoisting the scrap steel, a comprehensive inspection of the overhead crane, lifting equipment, LF (Ladle Furnace) equipment (such as electrode and furnace cover seals), and the molten steel level is required.

[0029] In some embodiments, alternatively, this application provides another method for smelting alloy steel, such as... Figure 2 As shown, the method includes: 202: Select scrap steel that meets the addition conditions as the additive material. The addition conditions are that the types of elements included in the scrap steel are within the range of the types of elements included in the molten steel. 204: Determine the maximum amount of additives based on the total amount of molten steel; 206: Divide the set amount of material into multiple sub-materials, and add the multiple sub-materials into the molten steel in sequence, with the set amount being less than or equal to the maximum amount; 208: Determine the temperature drop of the molten steel based on the set amount and the total amount of molten steel, and perform temperature compensation on the molten steel; 210: The content of each element in the molten steel is tested, and the molten steel is compensated according to the test results.

[0030] In this embodiment, the step of adding a predetermined amount of scrap steel to molten steel is specifically defined. When adding the predetermined amount of scrap steel to the molten steel, it needs to be added in batches. Specifically, the predetermined amount of scrap steel is divided into multiple sub-feeds, which are scrap steels that meet the addition conditions, and then these sub-feeds are added to the molten steel sequentially. Understandably, if the predetermined amount of scrap steel is added to the molten steel all at once, it can easily cause a sudden drop in the temperature of the molten steel. To avoid this problem, this application adopts a batch-addition method to add scrap steel to the molten steel to reduce the temperature drop.

[0031] Furthermore, scrap steel can be added to the molten steel by tilting the feedstock, i.e., any batch of feedstock can be added to the molten steel at an angle. This can reduce molten steel splashing.

[0032] In one possible embodiment, the amount of sub-additions in any group is less than or equal to 10 tons.

[0033] In some embodiments, the interval between two adjacent additions of sub-additions may be greater than or equal to a first duration.

[0034] In this embodiment, the step of adding a predetermined amount of additive to the molten steel is further defined. Specifically, the interval between two adjacent additions of the additive is greater than or equal to a first duration. During the interval between the two adjacent additions, the molten steel can be heated, thereby further reducing the temperature drop of the molten steel. The first duration can be 2 to 3 minutes.

[0035] In some embodiments, optionally, the weight of any group of additives is less than or equal to a preset weight.

[0036] In this embodiment, the weight of the sub-additions is limited. Specifically, the weight of any group of sub-additions is less than or equal to a preset weight. This avoids adding too much scrap steel to the molten steel at once, which reduces molten steel splashing and further minimizes the temperature drop of the molten steel. In one possible embodiment, the preset weight is 10 tons.

[0037] In some embodiments, alternatively, this application provides another method for smelting alloy steel, such as... Figure 3 As shown, the method includes: 302: Select scrap steel that meets the addition conditions as the additive material. The addition conditions are that the types of elements included in the scrap steel are within the range of the types of elements included in the molten steel. 304: The maximum amount of additives should be determined based on the total amount of molten steel. 306: Add a set amount of additive to the molten steel, the set amount being less than or equal to the maximum amount to be added; 308: Determine the temperature drop of the molten steel based on the set amount and the total amount of molten steel, and use electric arc heating to make the temperature of the molten steel reach the first target temperature; 310: The content of each element in the molten steel is tested, and the molten steel is compensated according to the test results.

[0038] In this embodiment, the alloy steel smelting method is further defined. The step of temperature compensation for molten steel specifically includes arc heating of the molten steel to bring its temperature to a first target temperature. The LF furnace has an arc heating function; after adding scrap steel to the molten steel, the arc heating function of the LF furnace is used to heat the molten steel, thereby causing the temperature of the molten steel to rise immediately, avoiding excessive temperature drop, and bringing the temperature of the molten steel to the first target temperature, which is the temperature that meets the casting requirements.

[0039] In some embodiments, alternatively, this application provides another method for smelting alloy steel, such as... Figure 4 As shown, the method includes: 402: Select scrap steel that meets the addition conditions as the additive material. The addition conditions are that the types of elements included in the scrap steel are within the range of the types of elements included in the molten steel. 404: The maximum amount of additives should be determined based on the total amount of molten steel. 406: Confirm whether the temperature of the molten steel is lower than the second target temperature. If the temperature of the molten steel is lower than the second target temperature, proceed to step 408, and then proceed to step 410. If the temperature of the molten steel is higher than or equal to the second target temperature, proceed to step 410. 408: Heat the molten steel to the second target temperature; 410: Add a set amount of additive to the molten steel, the set amount being less than or equal to the maximum amount to be added; 412: Determine the temperature drop of the molten steel based on the set amount and the total amount of molten steel, and perform temperature compensation on the molten steel; 414: The content of each element in the molten steel is tested, and the molten steel is compensated according to the test results.

[0040] In this embodiment, the smelting method for alloy steel is further defined. Before adding scrap steel to the molten steel, it is necessary to confirm whether the temperature of the molten steel meets the requirements for adding scrap steel. If the temperature of the molten steel is too low, the conditions for adding scrap steel are not met. Specifically, it is confirmed whether the temperature of the molten steel is lower than the second target temperature. If the temperature of the molten steel is lower than the second target temperature, the molten steel is heated to reach the second target temperature. If the temperature of the molten steel is higher than or equal to the second target temperature, scrap steel can be added to the molten steel, that is, the step of adding a set amount of feed material to the molten steel can be performed. In this way, it is possible to avoid adding scrap steel when the temperature of the molten steel is too low, which would cause the molten steel to solidify and prevent the bottom blowhole of the ladle from becoming blocked.

[0041] The second target temperature can be 100℃.

[0042] In some embodiments, alternatively, this application provides another method for smelting alloy steel, such as... Figure 5 As shown, the method includes: 502: Select scrap steel that meets the addition conditions as the additive material. The addition conditions are that the types of elements included in the scrap steel are within the range of the types of elements included in the molten steel. 504: The maximum amount of additives should be determined based on the total amount of molten steel. 506: Confirm whether the molten steel level is lower than the level threshold. If the molten steel level is lower than the level threshold, proceed to step 510. If the molten steel level is equal to or higher than the level threshold, proceed to step 508. 508: Stop adding the set amount of feedstock to the molten steel; 510: Add a set amount of additive to the molten steel, the set amount being less than or equal to the maximum amount to be added; 512: Determine the temperature drop of the molten steel based on the set amount and the total amount of molten steel, and perform temperature compensation on the molten steel; 514: The content of each element in the molten steel is tested, and the molten steel is compensated according to the test results.

[0043] In this embodiment, the smelting method for alloy steel is further defined. Before adding scrap steel to the molten steel, the molten steel level needs to be limited. If the molten steel level is too high, scrap steel cannot be added. Specifically, it is confirmed whether the molten steel level is below a threshold level. If the molten steel level is below the threshold level, scrap steel can be added, i.e., the step of adding a set amount of feed material to the molten steel is performed. If the molten steel level is equal to or higher than the threshold level, scrap steel cannot be added. Adding scrap steel at this time would cause the molten steel to become overfilled, which could easily lead to overflow. By limiting the molten steel level, the safety of alloy steel smelting can be improved, and overflow of molten steel can be avoided.

[0044] In some embodiments, alternatively, this application provides another method for smelting alloy steel, such as... Figure 6 As shown, the method includes: 602: Select scrap steel that meets the addition conditions as the additive material. The addition conditions are that the types of elements included in the scrap steel are within the range of the types of elements included in the molten steel. 604: The maximum amount of additives should be determined based on the total amount of molten steel. 606: Add a set amount of additive to molten steel, the set amount being less than or equal to the maximum amount to be added; 608: Stir the molten steel with argon and keep the stirred molten steel standing for a second time; 610: Determine the temperature drop of the molten steel based on the set amount and the total amount of molten steel, and perform temperature compensation on the molten steel; 612: The content of each element in the molten steel is tested, and the molten steel is compensated according to the test results.

[0045] In this embodiment, the alloy steel smelting method is further defined. After adding a predetermined amount of additive to the molten steel, the steel needs to be stirred and homogenized. Specifically, the molten steel is stirred by argon blowing, wherein the argon blowing flow rate is 300 NL / min to 1200 NL / min. This provides sufficient stirring kinetic energy to accelerate the melting of scrap steel and the homogenization of composition. The argon blowing time is greater than or equal to 5 minutes, thus ensuring minimum forced convection to ensure melting and initial mixing.

[0046] Furthermore, it is necessary to ensure that the distance between the scrap steel and the electrode is greater than or equal to 50cm to prevent the scrap steel from contacting the electrode and causing a short circuit that breaks the electrode.

[0047] In some embodiments, alternatively, this application provides another method for smelting alloy steel, such as... Figure 7 As shown, the method includes: 702: Select scrap steel that meets the addition conditions as the additive material. The addition conditions are that the types of elements included in the scrap steel are within the range of the types of elements included in the molten steel. 704: The maximum amount of additives should be determined based on the total amount of molten steel. 706: Add a set amount of additive to the molten steel, the set amount being less than or equal to the maximum amount to be added; 708: Determine the temperature drop of the molten steel based on the set amount and the total amount of molten steel, and perform temperature compensation on the molten steel; 710: The content of each element in the molten steel is tested. If the sulfur content in the molten steel is greater than the preset threshold, a desulfurizing agent is added to the molten steel.

[0048] In this embodiment, the alloy steel smelting method is further defined. After the scrap steel is completely melted into the molten steel, the content of each element in the molten steel is detected, and the composition of the molten steel is fine-tuned when it does not conform to expectations. Specifically, if the sulfur content in the molten steel exceeds the standard, that is, if the sulfur content is greater than a preset threshold, a desulfurizing agent needs to be added to the molten steel to reduce the sulfur content.

[0049] In this invention, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0050] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0051] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0052] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for smelting alloy steel, characterized in that, include: Select scrap steel that meets the addition conditions as the additive material. The addition conditions are that the types of elements included in the scrap steel are within the range of the types of elements included in the molten steel. The maximum amount of additive is determined based on the total amount of molten steel. A predetermined amount of the additive is added to the molten steel, wherein the predetermined amount is less than or equal to the maximum amount added; The temperature drop of the molten steel is determined based on the set amount and the total amount of molten steel, and temperature compensation is performed on the molten steel. The content of each element in the molten steel is detected, and the molten steel is compensated according to the detection results.

2. The alloy steel smelting method according to claim 1, characterized in that, The addition condition also includes that the length of the scrap steel is less than or equal to a preset length.

3. The alloy steel smelting method according to claim 1, characterized in that, The addition of a predetermined amount of additive to the molten steel includes: The set amount of feed material is divided into multiple groups of sub-feed materials, and the multiple groups of sub-feed materials are added to the molten steel in sequence.

4. The alloy steel smelting method according to claim 3, characterized in that, The time interval between two consecutive additions of the sub-addition material is greater than or equal to the first time interval.

5. The alloy steel smelting method according to claim 3, characterized in that, The weight of any group of added materials is less than or equal to the preset weight.

6. The alloy steel smelting method according to claim 1, characterized in that, The temperature compensation for the molten steel includes: The molten steel is heated by an electric arc to bring its temperature to a first target temperature.

7. The alloy steel smelting method according to claim 1, characterized in that, Before adding the predetermined amount of additive to the molten steel, the method further includes: Confirm whether the temperature of the molten steel is lower than the second target temperature; If the temperature of the molten steel is lower than the second target temperature, then the molten steel is heated to the second target temperature; If the temperature of the molten steel is higher than or equal to the second target temperature, then the first total amount of the additive is added to the molten steel.

8. The alloy steel smelting method according to claim 1, characterized in that, Before adding the predetermined amount of additive to the molten steel, the method further includes: Confirm whether the molten steel level is below the level threshold; If the liquid level of the molten steel is lower than the liquid level threshold, then the set amount of the additive is added to the molten steel; If the level of the molten steel is equal to or higher than the level threshold, then the addition of the set amount of additive to the molten steel shall be stopped.

9. The alloy steel smelting method according to claim 1, characterized in that, After adding the predetermined amount of additive to the molten steel, the process further includes: The molten steel is stirred by argon blowing and then kept still for a second time.

10. The alloy steel smelting method according to claim 1, characterized in that, The compensation process for the molten steel based on the test results includes: If the sulfur content in the molten steel exceeds a preset threshold, a desulfurizing agent is added to the molten steel.

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